Efficient perovskite solar cells employing a simply-processed CdS electron transport layer

In this report, redispersable CdS nanoparticles are synthesized via a specific one-step solvothermal reaction and are employed as electron-selective materials for organometal halide perovskite solar cells. The as-synthesized CdS nanoparticles can be well re-dispersed in toluene to form a uniform and stable CdS ink. On this basis, a CdS electron-selective contact layer can be directly prepared by spin-coating CdS ink and without a further annealing process. The CdS electron-selective contact layer has high optical transmittance at visible wavelengths. Its electron extraction and transfer properties are also investigated using current density-voltage curves, incident photocurrent conversion efficiency, stabilized current density and photoluminescence spectra. The use of a CdS electron-selective contact layer in a planar perovskite solar cell equipped with a Cs-0.05(MA(0.17)FA(0.83))(0.95)Pb(I0.83Br0.17)(3) light-absorption layer results in a high power conversion efficiency of 16.5%.